Fuel cells are useful for producing electrical energy based on an electrochemical reaction. One of the challenges associated with implementing fuel cells on a large scale has been the expense typically associated with the fuel cell components. For example, catalyst layers typically include expensive materials such as platinum. There have been various proposals for reducing the amount of platinum required to reduce the cost associated with fuel cells.
One proposal has been to use core-shell catalysts including a noble metal core with a shell of platinum deposited on the core. Such core-shell catalyst are considered promising for low temperature fuel cells, for example. Synthesizing core-shell catalysts according to some proposals includes establishing a copper monolayer on a palladium (or other noble metal) core and subsequently displacing the copper with a monolayer of platinum. Some of the challenges associated with proposed techniques in this regard include avoiding platinum cluster formation during the deposition process to achieve a platinum monolayer having desired characteristics. The type of constraints required to control the platinum deposition process tend to limit the batch size and that may detract from any economic benefits associated with utilizing core-shell catalysts.